Antinociceptive and cytotoxic activities of an epiphytic medicinal orchid: Vanda tessellata Roxb.

BACKGROUND Vanda tessellata (Orchidaceae) has been used in different sorts of ailments such as inflammations, rheumatism, dysentery, bronchitis, dyspepsia and fever in folk medicine. In this study we evaluated the antinociceptive and cytotoxic effect of methanol and aqueous extracts of V. tessellata leaf. METHODS Oral administration of V. tessellata aqueous (VTA) and methanol (VTM) leaf extracts at 200 and 400 mg/kg body weight (bw) doses were assessed for antinociceptive activity in acetic acid-induced writhing test, hot plate test, and tail immersion test in mice. In this study we also screened for cytotoxicity of the extracts by the brine shrimp (Artemia salina) lethality assay. RESULTS The extracts, at both doses, exhibited a significant (p < 0.05 - < 0.01) dose-dependent antinociceptive activity in hot plate and tail immersion test. The reaction time was increased to the thermal stimuli at 200 and 400 mg/kg doses up to 90 min. In acetic acid-induced writhing test, oral administration of VTA and VTM (200 and 400 mg/kg) also decreased the writhing significantly while compared to control. The dose 400 mg/kg showed maximum percentage of pain inhibition 42.37% and 45.08% for VTA and VTM respectively. Diclofenac sodium (10 mg/kg) and nalbuphine (10 mg/kg) were used as reference antinociceptive drugs. Very low cytotoxicity was observed on brine shrimps lethality assay. CONCLUSIONS The leaf extract has potential antinociceptive activity with minimum cytotoxicity. The present study supports the use of V. tessellata in different inflammatory disorders.